1. As imcome rises, more children survive to adulthood.
2. As income rise, few people dies each year.
3. As population increases, income per capital decrease:
   • Due to diminishing marginal product of labor.
4. Hence, in the long run, population froth will absorb any gain in income.

Depicted in a simple diagram

• Income per capita is on the horizontal axis.
• The vertical axis panel the death/birth rate.
• The lower panel depicts the rel;ationship between population and per capital income
  • It captures asusmption 3, if more resources such as akdn are relatively fixed, population groth reduces the marginal product of labor and results in each worker earning a lower income.
• Suppose per capita income exceeds
  • In this case, the birth rate will exceed death rate and population will grow
  • Grow in population will cause per capita income to fall
  • The fall of per capita income will cause death rate to rise and birth rate fall(less children surive to adulthood.)
  • The economy return to equilibrium
• Occatonal positive shock
  • such as a one-off improvement in technology or new crops
  • increase producticty and enable a period of population growth and temporary higher income.
  • However, it will return to in the end, as people have more babies that eat up the surplus.
  • Therefore, countries with more fertile land and higher technological level are only charaterized with higher population densities.

In the simple malthusian model, living standards are determined by the intersection of fertility and mortality.

The digram showed that the higher income per capita can be obtained if fertility is restrained.
Malthus considered this possibility, distingusihing it as a preventive check (opposed to a positive check: dieases and starvation) (pg 97)

• One example of preventive check was the practice of late marriage.
• European marriage pattern(EMP)(Hajnal 1965)(pg 97-98)
  • Women tends to marry in mid-twenties
  • Before modern period, female age at marriage was important in determining aggregate fertility.
  • Birth control within marraige was not widely practiced.
  • Fertility within marraige remained high.
  • In average, every two year women was not married reduce the number of children by one.
  • The European marrage pttern was asociated with small, nuclear households, based on a single married couple.(pg 98)
  • Prior to marraige, young people worked in other households, women make independent decistion. (Hajnal, 1982, p. 475)
  • Charateristics:
    • High age of first marriage: ≈ 25 for women.
    • Very low levels of illegitimacy.
    • ≈ 10% never marry.
    • Nuclear families rather than stem families (adult married children live with one set of parents in the latter).
• Pre-industrial societies outside the northwestern Europe (pg 98)
  • There, joint housholds, comprising two or more married couples, wer common.
    • Charaterized by universal and early marriage and high fertility.
• These two systems reacted differently to population pressure. In joint housholds, an icnrease in te popuulation might increase the underemployment of married adults.
• EMP allow more women to earn money indenpentntly prior to marriage, and engale them to make decision independently.(de Moor and Van Zanden, 2010)
• Labor markets played a critical role in this development.
• The origin of EMP is difficult to trace, but became prominent folloing black death.

Two claims:
EMP played an important role in restraining fertility and hence maintaily per capita income(Weak claim)
EMP played an importatn role in the transition to modern economic growth. (Strong claim)

• Voigtländer and Voth (2013a) argue that the demographic shock of the Black Death had a differential effect on Northern and Southern Europe.
  • Northern Europe: Land could be turned over to pastoral agriculture, increasing demand for female labor.
  • Southern Europe: Land more suited for arable farming.
• As pastoral farming increased the demand for female labor, it contributed to labor and marriage market outcomes that resulted in late marriages and restricted fertility (EMP).
  Industrialization and low-pressure demographic regime:
• Voigtländer and Voth (2006) simulate a model of the English economy between 1700 and 1850.
• They find that industrialization was dependent on England's low-pressure demographic regime.
• High-fertility regime leads to faster population growth, pushing down per capita incomes and reducing effective demand for manufactured goods.
• England's low birth rates prevented this scenario and allowed for sustained economic growth.
  EMP and human capital investment:
• Foreman-Peck (2011) argues that EMP, by lowering birth rates, also lowered death rates and encouraged investment in human capital.
• Families trade off quantity and quality of offspring in response to relative prices.
• Suggestive empirical evidence in 19th-century England shows low birth rates associated with lower infant mortality and greater human capital investments.

Dennision and Ogilvie(2014)

• Aruge that there is not relationship between EMP and sustained economic growth.
• EMP was the most developed in part in central Europe with economic stagnation.
• It was only England's uniqe demographic and fertitly esepcially responsive to economic condition.
• They show that hen measured the age of first marriage, EMP was less extreme in England than elsewhere.
• Intitution is not necessarily opposite to EMP arguments
  • Carmichael, de Pleijt, van Zanden, and de Moor (2016)
    • EMP was a reflection of a wider institution based on joint household and marraige based on cnsent.
    • It cannot simply measured by age of first marriage.
    • Economcally successful region with EMP instituions had lower marraige age than those with stagnating EMP regions.
  • EMP does not always simply reflect a voluntary decison between bride and groom.Dennision and Ogilvie(2014)
    • Local insitutions such as fuilds excluded women, and economically independent women were often harassed by landlords.

(Galor and Weil 2000), (Galor,2005), (Galor,2011)

• The transition from Malhusian Stagnation to modern economic growth has been stuied by Galor and co-authors.
• Unified growth theory
  • Galor proposed a unified theory of the transition from Malthusian stagation to sustained economic growth based on the incentive to invest in human capital.
  • Account two important developments:
    1. The gruadal increase in growth rates that occurred during the Industrial revolution.
    2. Demographic transitiion in the late 19th and early 20th century..
  • The demographic transition ensure income rose and decrease the increase in rate of natural population.
  • Begin with the fact that for most of history:
    • The rate of technological progress was low
    • Returns to investment in human capital were also slow.
      • Parent thus have little incentive to invest in education.
      • Invest in quantity over quality.
      • Lower per capital income.
  • Investment in human capital occur when the stock of human capital is enough that technological improvelemts is common.(pg 102)
    • It started with, the larger population bring the higher chance of major invention or new idea.
  • Overtime, the increase in stock of knowledge increase returns to human capital.
    • Furthermore increase rate of economic growth
    • The second phases of Industiral revolution after 1850 lead to widespread increase in demand for more educated workers.